1. Field of the Invention
This invention relates to improvements in a snack food product, process and apparatus for producing the same, and more particularly to the reduction in phase-locking of corrugated snack food chips.
2. Background Art
Corrugated or ridged snack food chips, e.g., potato chips, are well known and well liked by consumers. Frito-Lay, Inc., assignee of this invention, makes and sells substantial amounts of ridged potato chips under the trademarks O'GRADYS.TM. and RUFFLES.RTM.. These ridged or corrugated potato chips have corrugations on their opposing surfaces which are parallel ridges and valleys.
In the production of such chips, potatoes are cut into slices with the corrugations in the slices, washed and fried.
There has been a signficant problem in the art of such corrugated potato slices sticking together during the washing step and staying stuck together or "phase-locking" during the frying step. When the chips are phase-locked they are "clustered", and because these clusters are thicker than individual slices, they do not fry out completely and, as a result, have "soft" centers. This creates significant fried waste, which requires manual inspection and elimination. It is believed that surface tension is the cause of phase-locking of the corrugated slices. Because the corrugated slices have significantly more surface than flat chips, there is consequently more surface tension. This surface tension is so great that even significant agitation of frying oil will not separate "phase-locked" slices.
Although typically potato slices are washed in water prior to frying, one of the advances in the art of producing potato chips achieved by Frito-Lay, Inc. involves hot oil activation in which unwashed slices are heated in edible oil to activate the enzyme pectin methyl esterase, and no water is used during the washing step. This has significant advantages, see U.S. Pat. No. 4,503,127 granted Mar. 5, 1985, assigned to Frito-Lay, Inc. However, phase-locking of deeply corrugated chips such as O'GRADYS.TM., shown in U.S. Pat. No. 4,511,586 granted Apr. 16, 1985, assigned to Frito-Lay, Inc., occurs to such an extent that, as a practical matter, it is uneconomical to produce O'GRADYS.TM. chips by use of the hot oil activation process. Even though phase-locking was considered an insurmountable problem in producing O'GRADYS.TM. chips according to U.S. Pat. No. 4,511,586 utilizing the hot oil activation process of U.S. Pat. No. 4,503,127, it is also a possible problem in the manufacture of chips which are not ridged as deeply as O'GRADYS.TM. chips, and when washing in water rather than treating with hot oil. Previous to this invention, no solution to this problem was known and Frito-Lay, Inc. stopped processing O'GRADYS.TM. chips using hot oil activation as it was uneconomical to employ personnel to manually pick out and throw away already-fried, but clustered and otherwise unevenly fried phase-locked chips.